Aciduliprofundum boonei T469
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ABSTRACT:
PROVIDER: PRJNA38403 | ENA |
REPOSITORIES: ENA
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Project description:Casposons are a group of bacterial and archaeal DNA transposons encoding a specific integrase, termed casposase, which is homologous to the Cas1 enzyme responsible for the integration of new spacers into CRISPR loci. Here, we characterized the sequence motifs recognized by the casposase from a thermophilic archaeon Aciduliprofundum boonei. We identified a stretch of residues, located in the leader region upstream of the actual integration site, whose deletion or mutagenesis impaired the concerted integration reaction. However, deletions of two-thirds of the target site were fully functional. Various single-stranded 6-FAM-labelled oligonucleotides derived from casposon terminal inverted repeats were as efficiently incorporated as duplexes into the target site. This result suggests that, as in the case of spacer insertion by the CRISPR Cas1-Cas2 integrase, casposon integration involves splaying of the casposon termini, with single-stranded ends being the actual substrates. The sequence critical for incorporation was limited to the five terminal residues derived from the 3' end of the casposon. Furthermore, we characterize the casposase from Nitrosopumilus koreensis, a marine member of the phylum Thaumarchaeota, and show that it shares similar properties with the A. boonei enzyme, despite belonging to a different family. These findings further reinforce the mechanistic similarities and evolutionary connection between the casposons and the adaptation module of the CRISPR-Cas systems.
| S-EPMC6614799 | biostudies-literature
Project description:Aciduliprofundum boonei overview
| PRJNA36075 | ENA
Project description:Many archaea and bacteria have an adaptive immune system known as CRISPR which allows them to recognize and destroy foreign nucleic acid that they have previously encountered. Two CRISPR-associated proteins, Cas1 and Cas2, are required for the acquisition step of adaptation, in which fragments of foreign DNA are incorporated into the host CRISPR locus. Cas1 genes have also been found scattered in several archaeal and bacterial genomes, unassociated with CRISPR loci or other cas proteins. Rather, they are flanked by nearly identical inverted repeats and enclosed within direct repeats, suggesting that these genetic regions might be mobile elements ('casposons'). To investigate this possibility, we have characterized the in vitro activities of the putative Cas1 transposase ('casposase') from Aciduliprofundum boonei. The purified Cas1 casposase can integrate both short oligonucleotides with inverted repeat sequences and a 2.8 kb excised mini-casposon into target DNA. Casposon integration occurs without target specificity and generates 14-15 basepair target site duplications, consistent with those found in casposon host genomes. Thus, Cas1 casposases carry out similar biochemical reactions as the CRISPR Cas1-Cas2 complex but with opposite substrate specificities: casposases integrate specific sequences into random target sites, whereas CRISPR Cas1-Cas2 integrates essentially random sequences into a specific site in the CRISPR locus.
| S-EPMC4678821 | biostudies-literature
Project description:Genome reorganization by large scale indels, gene displacements, and horizontal gene transfers allow an organism to re-organize genes into operons (“operonization”) and explore novel strategies for adapting to its changing environment. We have characterized the process of operonization by mapping and comparing transcriptome structures (TSs) of four phylogenetically diverse exptremophilic archaea: a hydrogenotrophic methanogen (Methanococcus maripaludis S2), an anaerobic thermophile (Pyrococcus furiosis DSM 3638), an acidophilic and aerobic thermophile (Sulfolobus solfataricus P2), and a photoheterotrophic halophile (Halobacterium salinarum NRC-1). We demonstrate how the evolution of new transcriptional elements (promoters and terminators) is utilized as a mechanism to incorporate translocated, inverted, and newly acquired genes into existing gene regulatory programs. This SuperSeries is composed of the following subset Series: GSE26777: Methanococcus maripaludis S2 growth curve, tiling arrays GSE26778: Pyrococcus furiosus DSM 3638 growth curve, tiling arrays GSE26779: Sulfolobus solfataricus P2 growth curve, tiling arrays Refer to individual Series
2011-06-27 | E-GEOD-26782 | biostudies-arrayexpress
Project description:Genome reorganization by large scale indels, gene displacements, and horizontal gene transfers allow an organism to re-organize genes into operons (“operonization”) and explore novel strategies for adapting to its changing environment. We have characterized the process of operonization by mapping and comparing transcriptome structures (TSs) of four phylogenetically diverse exptremophilic archaea: a hydrogenotrophic methanogen (Methanococcus maripaludis S2), an anaerobic thermophile (Pyrococcus furiosis DSM 3638), an acidophilic and aerobic thermophile (Sulfolobus solfataricus P2), and a photoheterotrophic halophile (Halobacterium salinarum NRC-1). We demonstrate how the evolution of new transcriptional elements (promoters and terminators) is utilized as a mechanism to incorporate translocated, inverted, and newly acquired genes into existing gene regulatory programs. This SuperSeries is composed of the SubSeries listed below.
2011-06-27 | GSE26782 | GEO